Bay Area expert explains how Giffords survived

Brain trauma patients like Arizona Rep. Gabrielle Giffords, who suffered gunshot wounds to the brain, not only face slim chances of survival, but often a lifetime of hardships.

Dr. Geoffrey Manley heads the neurosurgery department at San Francisco General Hospital, which is one of the Bay Area's "Level One" trauma centers. He believes having a similar facility in Tucson, along with a talented team of doctors on hand, helped save lives Saturday.

"It is like any other injury. You have swelling that comes after the injury and so what they've done essentially, removed a large portion of bone here to allow the brain to swell," he explained.

Surgeons removed part of Giffords' skull to relieve the pressure on her injured brain. Military surgeons have used that same procedure to save the lives of many troops injured in combat. They also performed one on ABC news anchor Bob Woodruff after he was wounded by a roadside bomb in Iraq.